With fast development of Internet technologies and services, Internet media content increases and becomes diversified, including music, movies, TV series, news, self-made video clips, and the like. Popularity of Internet media greatly enriches visual and aural experience of users. To realize that a device in a home network also has a content sharing function while playing Internet media content, that is, to switch Internet media content played on one device to another device for playing, currently, the device in the home network mainly uses a Digital Living Network Alliance (Digital Living Network Alliance, DLNA for short) device. The device uses a universal plug and play (Universal Plug and Play, UPnP for short) Audio with Video (UPnP Audio & Video, UPnP AV for short) standard. That is, in a DLNA protocol architecture, DLNA devices can implement a series of steps such as device discovery, device service description, device control, event transfer, and content presentation by using a UPnP device architecture and the UPnP AV protocol as long as the DLNA devices are connected to a same wireless local area network (Wireless Local Area Networks, WLAN for short), thereby implementing transmission and sharing of media content between the DLNA devices.
In addition, according to the DLNA specification, when a DLNA device goes online, the DLNA device multicasts an online message or a search message to a whole WLAN for mutual discovery of devices. All DLNA devices that are connected to the WLAN network and have a control function can receive an online message multicast by another DLNA device having a media service function, and acquire a media content list stored by the DLNA device having the media service function.
However, when a WLAN accessed by the DLNA device having the media service function is a public Wi-Fi network such as a network at an airport, in a shopping mall, or in a dining hall, this device and a service mechanism have a risk of privacy leakage in this case, that is, any control point device that accesses the public Wi-Fi network can discover an online DLNA device and acquire shared media content of the DLNA device, but the DLAN device knows nothing about this, and consequently, security of the shared media content of the DLAN device is poor.